RGunn I'm befuddled at how you refuse to accept the findings from different sources. If you have been paying any attention over your long and studious reloading career you surely would have noticed by now that no two outfits data will completely agree.
Until now you have said little if anything that I've seen about how you "worked" into that almost suicidal charge. You also let on that you've well versed in reloading , so it seems to me that you would know that a case that was a little long isn't to likely to pop primer pockets, unless you were already way over the top on pressure. Also I suspect you had to fire that charge or something similar multiple times to get a 40-82 case to stretch enough that it could become dangerous. It could of been that that case stretched as well as blew the primer with that dangerous overload you had stuffed into it. As I've said before that you didn't lose any body parts is certainly a testiment to the quality of that CSharps.
I also can't understand why you won't take SAAMI's pressure specs on cartridges as proof of how much pressure blackpowder and cartridges generate. The 45-70 (Trapdoor) is set at 28000 psi, I would expect that's probably what would be when loaded with a 500 gr bullet and 70 grs of 3ff. 2f loads will likely be a bit less, another example is the 38-55 it specs at 30,000 cup.
As the old Ideal manual stated it's hard to get into trouble when using the PROPER granulation of black powder.
